Use of Enzymes to Improve Waterflood Performance
Hamidreza Nasiri, Kristine Spildo, and Arne Skauge
Center for Integrated Petroleum Research (CIPR), Bergen, Norway
This paper was prepared for presentation at the International Symposium of the
Society of Core Analysts held in Noordwijk, The Netherlands 27-30 September, 2009
A variety of enhanced oil recovery (EOR) methods have been developed and applied to improve waterflood efficiency. These methods aim at improving both microscopic displacement efficiency and macroscopic reservoir sweep. In addition to reducing residual oil saturation and increasing contact with unswept oil, fluid flow improvement has also been a focus of EOR technologies. A change in wettability may lead to a favorable change in fluid flow properties. Another significant focus has been to improve spontaneous imbibition to enhance oil recovery from matrix rock in fractured reservoirs.
We have been investigating to what extent enzymes-proteins can change the wettability state of an oil reservoir formation and possibly lead to increased oil recovery by waterflooding. Enzymes consist of water soluble proteins which may act as catalysts and encourage interactions between oil and water that may release oil from the grain faces of a porous medium.
This work reports the results of contact angle measurements to quantify the changes in wettability resulting from different concentrations of enzyme-in-brine solutions. Several different enzyme-protein mixtures have been investigated. The experimental results confirm a considerable decrease in contact angle with enzyme solutions compared to an untreated brine. In all cases, the change due to added enzymes was towards a more water-wet state. The paper will also discuss core flood results using enzyme-in-brine solutions for waterflooding Berea sandstone cores aged in crude oil.
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About the Society of Core Analysts
The name of this organization is the Society of Core Analysts (SCA) and was founded in 1986. This organization is a Chapter-at-Large of The Society of Petrophysicists and Well Log Analysts (SPWLA) and is established with two objectives:
- To promote the aims, purposes, and membership of the SPWLA which is a non-profit scientific organization.
- To serve the interests of all persons who use or obtain reservoir evaluation information from rock and core samples.
As a guide for fulfilment of the first objective, this Chapter stands responsible to, and subject to, the rules and regulations of the SPWLA.
As a means toward the second objective this Chapter will sponsor technical speakers, projects, and presentation of papers dealing with formation evaluation. This Chapter will hold membership open to all core analysts, log analysts, geologists, geophysicists engineers, service company personnel and all others interested in the study of rocks and their interstitial fluids. This Chapter will also actively encourage membership and participation in the activities of the SPWLA.